| 摘要 |
PURPOSE:To easily correct temperature characteristics of a circuit which executes the nonlinear conversion by processing an output of plural color detection means with the nonlinear conversion means such as one logarithm compressing circuit, etc. CONSTITUTION:The light currents of R light, B light and G light detected with photodetecting diodes 1, 2 and 8 are switched with switches 9-16 and are in order added to a logarithm compressing circuit consisting of a diode 17 and an amplifier 20. The switches 9-14 are controlled to ON-state and OFF-state with the control signal from terminals 9c-11c and the switches 15 and 16 are controlled to ON-state and OFF-state with terminals 15c and 16c respectively. Next, the output of the logarithm-compressed amplifier 20 is taken out through the amplifier 21 to a terminal 42. The output from the terminal 42 is given to the operation means, is concurrently processed and is calculated. As such, since the output is processed by one nonlinear conversion means, the temperature characteristics of the circuit by which nonlinear conversion is executed can be easily corrected. |
